Electronic devices containing organic, organometallic and/or polymeric semiconductors are becoming increasingly important, and are being used in many commercial products for reasons of cost and because of their performance. Examples here include organic-based charge transport materials (for example triarylamine-based hole transporters) in photocopiers, organic or polymeric light-emitting diodes (OLEDs or PLEDs) and in readout and display devices or organic photoreceptors in photocopiers. Organic solar cells (O-SCs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic integrated circuits (O-ICs), organic optical amplifiers and organic laser diodes (O-lasers) are at an advanced stage of development and may have great future significance.
Many of these electronic devices, irrespective of the respective end use, have the following general substrate structure which can be adjusted for the particular application:    (1) substrate,    (2) electrode, frequently metallic or inorganic, but also composed of organic or polymeric conductive materials,    (3) charge injection layer(s) or interlayer(s), for example to compensate for unevenness in the electrode (“planarization layer”), frequently composed of a conductive doped polymer,    (4) organic semiconductor,    (5) possibly further charge transport, charge injection or charge blocker layers,    (6) counterelectrode, materials as specified in (2),    (7) encapsulation.
The above arrangement is the general structure of an organic electronic device, it being possible to combine various layers, such that the result in the simplest case is an arrangement composed of two electrodes with an organic layer in between. In this case, the organic layer fulfils all functions including the emission of light in the case of OLEDs. A system of this kind is described, for example, in WO 90/13148 A1, based on poly(p-phenylenes).
Electronic devices containing carbazoles having dibenzofuran or dibenzothiophene substituents are known inter alia from publications US 2012/0289708, WO 2012/086170, US 2012/071668, US 2012/091887, WO 2012/033108, CN 102850334, WO 2013/032278, US 2012/0256169, WO 2012/036482; WO 2013/5923, WO 2013/084885, WO 2013/102992, WO 2013/084881, WO 2012/067425, US 2011/260138, WO 2011/125680, WO 2011/122132, WO 2013/109045, WO 2013/151297, WO 2013/41176, WO 2012/108389, KR 2013/0025087 and KR 2013/0112342.
Known electronic devices have a useful profile of properties. However, there is a constant need to improve the properties of these devices.
These properties especially include the energy efficiency with which an electronic device solves the problem defined. In the case of organic light-emitting diodes, which may be based either on low molecular weight compounds or on polymeric materials, the light yield in particular should be sufficiently high that a minimum amount of electrical power has to be applied to achieve a particular luminous flux. In addition, a minimum voltage should also be necessary to achieve a defined luminance. A further particular problem is the lifetime of the electronic devices.